diff --git a/common/tf_log.c b/common/tf_log.c
index 6da1e85..422959f 100644
--- a/common/tf_log.c
+++ b/common/tf_log.c
@@ -28,19 +28,21 @@
 	log_level = fmt[0];
 
 	/* Verify that log_level is one of LOG_MARKER_* macro defined in debug.h */
-	assert(log_level && log_level <= LOG_LEVEL_VERBOSE);
-	assert(log_level % 10 == 0);
+	assert((log_level > 0U) && (log_level <= LOG_LEVEL_VERBOSE));
+	assert((log_level % 10U) == 0U);
 
 	if (log_level > max_log_level)
 		return;
 
 	prefix_str = plat_log_get_prefix(log_level);
 
-	while (*prefix_str)
-		putchar(*prefix_str++);
+	while (*prefix_str != '\0') {
+		(void)putchar(*prefix_str);
+		prefix_str++;
+	}
 
 	va_start(args, fmt);
-	vprintf(fmt + 1, args);
+	(void)vprintf(fmt + 1, args);
 	va_end(args);
 }
 
@@ -52,10 +54,9 @@
 void tf_log_set_max_level(unsigned int log_level)
 {
 	assert(log_level <= LOG_LEVEL_VERBOSE);
-	assert((log_level % 10) == 0);
+	assert((log_level % 10U) == 0U);
 
 	/* Cap log_level to the compile time maximum. */
-	if (log_level < LOG_LEVEL)
+	if (log_level < (unsigned int)LOG_LEVEL)
 		max_log_level = log_level;
-
 }
diff --git a/include/common/debug.h b/include/common/debug.h
index ab3e15a..8ee55b8 100644
--- a/include/common/debug.h
+++ b/include/common/debug.h
@@ -7,6 +7,8 @@
 #ifndef DEBUG_H
 #define DEBUG_H
 
+#include <utils_def.h>
+
 /*
  * The log output macros print output to the console. These macros produce
  * compiled log output only if the LOG_LEVEL defined in the makefile (or the
@@ -18,12 +20,12 @@
  * WARN("Warning %s.\n", "message") -> WARNING: Warning message.
  */
 
-#define LOG_LEVEL_NONE			0
-#define LOG_LEVEL_ERROR			10
-#define LOG_LEVEL_NOTICE		20
-#define LOG_LEVEL_WARNING		30
-#define LOG_LEVEL_INFO			40
-#define LOG_LEVEL_VERBOSE		50
+#define LOG_LEVEL_NONE			U(0)
+#define LOG_LEVEL_ERROR			U(10)
+#define LOG_LEVEL_NOTICE		U(20)
+#define LOG_LEVEL_WARNING		U(30)
+#define LOG_LEVEL_INFO			U(40)
+#define LOG_LEVEL_VERBOSE		U(50)
 
 #ifndef __ASSEMBLY__
 #include <cdefs.h>
@@ -50,10 +52,10 @@
  */
 #define no_tf_log(fmt, ...)				\
 	do {						\
-		if (0) {				\
+		if (false) {				\
 			tf_log(fmt, ##__VA_ARGS__);	\
 		}					\
-	} while (0)
+	} while (false)
 
 #if LOG_LEVEL >= LOG_LEVEL_NOTICE
 # define NOTICE(...)	tf_log(LOG_MARKER_NOTICE __VA_ARGS__)
diff --git a/plat/common/plat_log_common.c b/plat/common/plat_log_common.c
index 30dcb12..49e1c15 100644
--- a/plat/common/plat_log_common.c
+++ b/plat/common/plat_log_common.c
@@ -1,25 +1,28 @@
 /*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#include <assert.h>
 #include <debug.h>
-#include <platform.h>
 
 /* Allow platforms to override the log prefix string */
 #pragma weak plat_log_get_prefix
 
-static const char *prefix_str[] = {
+static const char *plat_prefix_str[] = {
 	"ERROR:   ", "NOTICE:  ", "WARNING: ", "INFO:    ", "VERBOSE: "};
 
 const char *plat_log_get_prefix(unsigned int log_level)
 {
-	if (log_level < LOG_LEVEL_ERROR)
-		log_level = LOG_LEVEL_ERROR;
-	else if (log_level > LOG_LEVEL_VERBOSE)
-		log_level = LOG_LEVEL_VERBOSE;
+	unsigned int level;
+
+	if (log_level < LOG_LEVEL_ERROR) {
+		level = LOG_LEVEL_ERROR;
+	} else if (log_level > LOG_LEVEL_VERBOSE) {
+		level = LOG_LEVEL_VERBOSE;
+	} else {
+		level = log_level;
+	}
 
-	return prefix_str[(log_level/10) - 1];
+	return plat_prefix_str[(level / 10U) - 1U];
 }